首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1751040篇
  免费   129237篇
  国内免费   4811篇
耳鼻咽喉   22791篇
儿科学   57168篇
妇产科学   47921篇
基础医学   265089篇
口腔科学   48407篇
临床医学   165383篇
内科学   332960篇
皮肤病学   36451篇
神经病学   141458篇
特种医学   63467篇
外国民族医学   423篇
外科学   248134篇
综合类   36201篇
现状与发展   1篇
一般理论   570篇
预防医学   146097篇
眼科学   39312篇
药学   131415篇
  6篇
中国医学   3990篇
肿瘤学   97844篇
  2019年   14322篇
  2018年   19970篇
  2017年   15113篇
  2016年   16402篇
  2015年   18709篇
  2014年   25653篇
  2013年   39763篇
  2012年   54401篇
  2011年   58101篇
  2010年   33829篇
  2009年   31204篇
  2008年   53720篇
  2007年   56855篇
  2006年   57273篇
  2005年   55199篇
  2004年   52963篇
  2003年   50372篇
  2002年   49039篇
  2001年   79523篇
  2000年   82078篇
  1999年   68490篇
  1998年   19035篇
  1997年   17130篇
  1996年   17214篇
  1995年   16247篇
  1994年   15157篇
  1993年   14294篇
  1992年   54079篇
  1991年   53674篇
  1990年   52541篇
  1989年   50054篇
  1988年   46399篇
  1987年   45385篇
  1986年   43225篇
  1985年   41307篇
  1984年   30953篇
  1983年   26342篇
  1982年   15550篇
  1979年   28607篇
  1978年   20496篇
  1977年   16871篇
  1976年   16502篇
  1975年   17406篇
  1974年   21156篇
  1973年   20435篇
  1972年   19268篇
  1971年   18119篇
  1970年   16753篇
  1969年   15500篇
  1968年   14664篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
901.
FURST  A L; SHAMBA  E 《Family practice》1989,6(3):177-181
An audit of ‘deficient outcome’ involves the step-by-stepanalysis of every event preceding the occurrence of a preventablemedical outcome in order to determine exactly what went wrong.This paper describes methodological problems and related issuesassociated with a deficient outcome audit undertaken on fivestillbirths which occurred in a rural family medical practiceIsrael between 1985 and 1987. Problems included initial officialdisinterest towards the audit, and the high levels of suspicionand antagonism which it aroused in hospital staff approachedfor information. The problematic aspect of such audits needsmore attention. The importance of this type of audit for establishing the precisereasons for perinatal deaths, and thus for maintaining antenatalcare standards is discussed. In view of the small numbers ofsuch events likely to occur within any one family practice itis not only feasible but also desirable for more family doctorsto carry out such audits routinely, despite the difficultieswhich are involved.  相似文献   
902.
903.
It is well known that fibroblasts are a main source of extracellular matrix synthesis necessary for tissue repair. In addition, macrophages secrete products that are known to modulate synthesis of extracellular matrix. Accordingly, we studied the incorporation of [3H]thymidine, [3H]proline, and [35S]sulfate into macromolecules produced by fibroblasts recovered from the site of peritoneal tissue repair cultured with and without spent media from postsurgical peritoneal macrophages. Rabbits underwent resection and reanastomosis of their small intestines. Peritoneal exudative cells (PEC) were then collected on postsurgical day 5 and day 10 as well as from nonsurgical controls, separated by discontinuous Percoll gradient centrifugation, and cultured for 48 h. A second group of rabbits underwent peritoneal wall abrasion from which fibroblast tissue repair cells (TRC) were collected from the site of injury at postsurgical day 7 and maintained in culture for varying times. Incorporation of radiolabeled precursors into DNA, collagen, and sulfated proteoglycans was determined. Incorporation of [3H]thymidine and [3H]proline into untreated TRC gradually decreased with culture duration. Conversely, [35S]sulfate incorporation gradually increased during prolonged culture. Macrophage spent media increased the levels of [3H]thymidine incorporation by the TRC. [3H]Proline and [35S]sulfate incorporation into TRC were also stimulated by macrophage spent media. However, this stimulation may be due to the enhanced proliferation of TRC by macrophage spent media. In conclusion, tissue repair fibroblasts are activated for postsurgical repair at the site of injury by many factors including secretory products from postsurgical macrophages.  相似文献   
904.
In open chest dogs myocardial ischemia was induced by formation of an occlusive thrombus in the left anterior circumflex artery (LCX). Reperfusion of the LCX was achieved by infusion of the fibrin specific recombinant single-chain urokinase-type plasminogen activator (r-scu-PA). The myocardial salvage by r-scu-PA alone and in combination with the epoprostenol (prostacyclin) analog taprostene (CG 4203) was compared. There were four experimental groups: group 1 (n = 4) did not receive any treatment after LCX thrombosis; in group 2 (n = 9) at 100 min after LCX thrombosis r-scu-PA (20 micrograms.kg-1.min-1 i.v. for 30 min) was infused; in groups 3 and 4 treatment with taprostene started concomitantly with r-scu-PA infusion. The taprostene infusions lasted for 120 min and the doses were 0.1 microgram.kg-1.min-1 in group 3 (n = 6) and 0.215 microgram.kg-1.min-1 in group 4 (n = 6). Time to r-scu-PA-induced recanalisation ranged from 18-22 min with no significant difference between groups 2-4. Percent of left ventricle at risk did not differ between the groups. Infarct size as percent of the risk zone was 48.3 +/- 7.7 in group 1, 25.3 +/- 3.7 in group 2, 21.3 +/- 6.5 in group 3 and 17.1 +/- 3.5 in group 4 (p less than 0.05 groups 2-4 vs group 1). Incidence of ectopic beats increased after r-scu-PA-induced reperfusion in groups 2-4, but was significantly reduced by taprostene.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
905.
906.
907.
The accumulation of 201Tl in tumor and inflammatory tissues were small. However, this nuclide showed a high concentration in viable tumor tissue, less in connective tissue (containing inflammatory tissue), and was not seen in necrotic tumor tissue regardless of the time after administration of 201Tl(I)-chloride. In inflammatory lesions, 201Tl accumulated in subcutaneous tissue infiltrated with neutrophils and macrophages, and quite large amounts of this nuclide were accumulated in subcutaneous tissue and sites where neutrophils were crowded. Most 201Tl existed in a free form in the fluid of tumor and inflammatory tissues regardless of the time after administration. A small amount of this nuclide was localized in the nuclear, mitochondrial and microsomal fractions in these tissues, and the nuclide was bound to protein in these fractions. The distribution of 201Tl(III)-chloride in tumor bearing animals was essentially the same as that of 201Tl(I)-chloride.  相似文献   
908.
909.
A total of 42 patients with recurrent superficial bladder tumors or carcinoma in situ entered a prospective, randomized trial to compare the efficacy of bacillus Calmette-Guerin therapy with and without quarterly maintenance instillations of bacillus Calmette-Guerin. Maintenance therapy did not reduce further bladder tumor recurrence rates or the interval to recurrence in patients who responded to the initial course of therapy. However, prolongation of toxicity was observed with maintenance bacillus Calmette-Guerin therapy.  相似文献   
910.
Kojic amine [2-(aminomethyl)-5-hydroxy-4H-pyran-4-one], an analogue of gamma-aminobutyric acid (GABA), produced dose-related, but short-lived, antinociceptive activity in the 48 degrees C [ED50 = 9.2 (8.2-10.3) mg/kg i.p.] and 55 degrees C [ED50 = 13.8 (12.2-15.7) mg/kg i.p.] hot-plate tests in the mouse. The antinociceptive activity of kojic amine at 48 degrees C was found to be insensitive to bicuculline (1.0 mg/kg i.p.) and picrotoxin (0.5 mg/kg i.p.). At this temperature, antinociception was distinctly separate from the impairment of motor function (measured by a rotorod assay) and was not significantly affected by prior treatment with the cholinergic antagonist, atropine sulfate (10.0 mg/kg i.p.). However, at 55 degrees C, the antinociceptive effect of a large dose (20 mg/kg i.p.) of kojic amine was significantly attenuated by similar pretreatment with atropine sulfate, but not by the peripheral cholinergic antagonist, atropine methylnitrate (10.0 mg/kg i.p.). Kojic amine exhibited no significant interaction with haloperidol (0.5 mg/kg i.p.) at this temperature. In animals made tolerant to morphine, THIP or baclofen, there was analgesic cross-tolerance between kojic amine, morphine and baclofen but not between kojic amine and THIP. It is suggested that kojic amine-induced antinociception is similar to that produced by both THIP and baclofen. Thus, kojic amine represents a unique tool with which to study GABA-ergic antinociceptive processes.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号